Change times reported from io resource meta data to be milliseconds since epoch

Change times reported from io resource meta data to be milliseconds since epoch

Change tests accordingly (and add a few extra tests)

Move the logic to the _IOResource class to only have one datetime and one stopwatch.

R=johnmccutchan@google.com, sgjesse@google.com
BUG=

Committed: https://github.com/dart-lang/sdk/commit/f3f358e5f38829f3284d7f922f2393d0803115dd

[Søren Gjesse, 2015-09-14 12:37:53]

lgtm

[Cutch, 2015-09-14 14:23:32]

johnmccutchan@google.com changed reviewers:
+ johnmccutchan@google.com

[Cutch, 2015-09-14 14:23:32]

lgtm with one big DBC about service protocol field names being 'dartCamelCase'.

https://codereview.chromium.org/1341733003/diff/1/runtime/observatory/tests/s...
File runtime/observatory/tests/service/process_service_test.dart (right):

https://codereview.chromium.org/1341733003/diff/1/runtime/observatory/tests/s...
runtime/observatory/tests/service/process_service_test.dart:97:
expect(first['started_at'], greaterThan(0));
DBC- these field names should be dartCamelCase

[ricow1, 2015-09-14 15:57:46]

https://codereview.chromium.org/1341733003/diff/1/runtime/observatory/tests/s...
File runtime/observatory/tests/service/process_service_test.dart (right):

https://codereview.chromium.org/1341733003/diff/1/runtime/observatory/tests/s...
runtime/observatory/tests/service/process_service_test.dart:97:
expect(first['started_at'], greaterThan(0));
On 2015/09/14 14:23:32, Cutch wrote:
> DBC- these field names should be dartCamelCase

haha, I actually tried to be consistent and used underbars. I will change
everything in a follow up

[ricow1, 2015-09-15 05:42:16]

Committed patchset #1 (id:1) manually as
f3f358e5f38829f3284d7f922f2393d0803115dd (presubmit successful).